PROUST, Alain; MISTRAS Group, S.A.; France
Proust, A.; MISTRAS Group SA; France
Kefferstein, R.; ArcelorMittal Fos-sur-Mer; France
Al Hai, O.; MISTRAS Group SA; France
Crucq, D.; ArcelorMittal Fos-sur-Mer; France
Session: Acoustic Emission 1
Time: 15:20 - 15:40
The plant of ArcelorMittal Fos-sur-Mer (France) is producing 4 million tons per year of hot rolled steel coils.
A significant part of the production is shipped by boats.
Two Titan harbor cranes are used in order to transfer the 40 tons coils on boats.
These cranes have been manufactured in the 70’s and some fatigue cracks have been discovered in 2015. Significant repairs were realized on the metallic structure and inspection plan has been modified and optimized with conventional NDT methods (US, ACFM, MT…)
In order to detect unknown fatigue cracks propagation or initiation, an Acoustic Emission monitoring has been installed on the two harbor cranes. Especially for areas where traditional nondestructive testing methods are difficult to use.
After the proof tests, a specific procedure has been defined to set the instrumentation. Then an appropriate signal processing has been developed using pattern recognition analysis with Noesis software to characterize and identify several AE sources as fretting noises due to crane rotation, in service shocks, mechanical impacts…
The AE results of the monitoring of the first months indicate the activity of sources that are correlated with propagating fatigue cracks detected by dye penetrant and ultrasonic in area where even visual inspection is sometime difficult to perform. AE has demonstrated also the ability to verify in such conditions if a known indication is propagating or not.
Acoustic Emission monitoring has been pushed forward as a very flexible and powerful nondestructive tool for in service monitoring of complex machinery as harbour cranes or overhead travelling cranes. Included in the inspection plan it gives information about the propagating defect in real time allowing to an efficient maintenance policy.